Electric annunciator



(No Model.) 2 Sheets-Sheet 1.

J. W. HOFFMAN.

ELECTRIC ANNUNGIATOR. No. 377,256. Patented Jan. 31, 1888.

'74 maaa 0-5 Jami 152K i I @L'icu K374 N. PETERS. Phutn Lilhugnphar,Washingtan, D. C,

2 Sheets-Sheet 2.

(No Model.)

J. W. HOFFMAN. ELECTRIC ANNUNOIATOIL,

No. 377,256. Patented Jan. 31, 1888.

74 aea UNITED STATES ATENT Urrrcn.

JOHN XVILLIAM HOFFMAN, OF PULLMAN, ILLINOIS.

ELECTRIC ANNUNCIATOR.

SPECIFICATIQN forming part of Letters Patent No. 377,256, dated January31, 1888.

Application filed March 24, 1887. Serial No. 232,322.

To all whom it may concern.-

Be it known that I. J OHN WILLIAM HOFF- MAN, a citizen of the UnitedStates, residing at Pullman, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in ElectricAnnuneiators, of which the following is a specification.

This invention relates to an improvement in electric annunciatorswherein each of the several index-hands or other devices usuallyemployed for denoting the particular locality of a call is at oneextremity of its throw or movement held subject to the position of thearmature of an electro-magnet. which latter, when excited, serves toattract the armature, so as to release the index-hand or other likedevice and permit the same to swing or move to the opposite extreme ofits permitted movement, thereby indicating by its change of positionthat a call has been made from the particular room or other locality itis employed to represent.

A prominent feature of my invention re lates to the provision of simpleand efficient means for holding the index-hand or indicating devicepositively subject to the position of and securely locked by thearmature of the electro-inagnet as long as the armature remainsunattracted, but at the same time permitting the free and readyreleasement of the index hand or indicating device from the control ofthe armature as soon as the latter is attracted,thereby allowing thearmature to stand readily responsive to the attractive energy of themagnet.

A desirable and important object involved in the foregoing featureconsists in the avoidance of any accidental displacement of theindex-hand or indicating device from the control of the armature byreason of the jolting motion of a railway-car wherein the annuneiatormay be placed, thereby preventing the occurrence of false indications ofcalls and promoting the efiiciency and utility of electric annunciatorsfor service upon railway-cars.

Among the remaining features of myinvention may be noted certain detailsinvolving the following several objectsto wit, to vary or adjust theextent of locking contact between the armatu re and an arm upon thespindle of an indicator-hand; to vary the extent of throw or movement onthe part of theindeX-hand or indicating .device, whereby a uniformity of(No model.)

throw can be maintained throughout the en tire set or sets ofindex-hands usually employed; to limit the movement of the armaturetoward the magnet, so as to prevent ao tual contact between the two, andthereby avoid any liability of the armature clinging to theelectro-magnet in case the latter should become permanently magnetizedto an extent which would otherwise interfere with the free working ofthe apparatus.

To the attainment of all of the foregoing ends my invention consists inmatters hereinafter described, and particularly pointed out in theclaims.

In the drawings, Figure 1 represents in rear elevation an electricannunciator embodying my invention. Fig. 2 represents in rear elevationa portion of the back plate with the devices for controlling one of theindex-hands or indicating devices, the position ofthe armature beingsuch as to lock the index-hand. Fig. 3 is a view similar to thepreceding figure, but representing a section taken through the severalguide-posts and the magnet on a plane parallel with the back plate,theslide for lifting the arm of the index hand spindle being represented indotted lines. Fig. 4 is a view similar to the last preceding figure, butwith the arm of the indexhand spindle at the lowest limit of its throw.This view also represents in dotted lines the position of the armaturewhen it is attracted by the magnet. Fig. 5 is an edge view of thedevices shown in Fig. 2, with portions of two of the guide-postsbrokenaway for convenience of illustration.

In the several foregoing figures the usual connections between a batteryand the several electro-magnets A, and also the usual connectionsbetween the electro-magnets and the push or pull buttons, that will inpractice be disposed at points from whence calls are to be sent, areomitted, since these matters are common in electric annunciators andwell known to those skilled in the art.

It will also be understood that an electric call-bell can be mountedupon the frame or case B, to be rung, as usual, when the current isdirected through any one of the electromagnets, and that the number ofelectro-magnets desirably secured upon an ordinary brass back plate, C,will be in correspondence with the number of index-hands, which lattercan be secured upon oscillatory spindles and arranged in sets or rowsopposite the front of the case, as usual. I

With regard to my improved devices for controlling any one of theindex-hands or indicating devices, particular reference may be made tothe last four figures of the drawings, each of which includes theoscillatory spindle D of an index-hand, D, such as shown in Fig. 5,wherein the position of the index for denoting a call is indicated indotted lines.

The spindle of the index hand or device canries an arm, D, which saidarm is rigid with the spindle and secured thereto a'short distance backfromjone of its ends.

The armature A consists of an oscillatory bar which is made eitherstraight or slightly curved from end to end and pivoted at apointbetween its ends. The upper end of the armature extends between a coupleof cam-stops, E and F,which serve to determine the extent of its throwor vibratory movement,while thelower end portion of the'armature hangsopposite a portion of the core of the magnet that is exposed between theback plate and the coil of the electro-magnet.

The upper end of the armature is normally held against the cam-stop E bythe action of a spr ng, G. This spring is at its lower end secured to astud, G, upon the back plate, and is arranged with its free upper endbearing against the upper end portion of the armature in a manner tonormally hold the upper end of the armature against the cam-stop E, asaforesaid, and thereby hold the lower end of the armature off from themagnet.

The arm D of the index device will, when free from the armature, dropsubstantially into the position shown in Fig. 4,wherein the limit of thedown throw or swing of the arm is determined by a cam-stop, H. The armD" is to be swung up from its said lowered position for the purpose ofrestoring the index-hand to the position it is to occupy preparatory toa call or signal and of placing the said arm in en gagement with thearmature, in order to hold the index-hand in position until a call ismade and the armature drawn away from its engagement with the arm.

During the upward swing of the arm for the foregoing purposes the corner(2 of the arm will, in striking and passing the armature, force thelower end of the latter toward the magnet, so as to swing the entirearmature to some extent against the resistance of the spring G. As soon,however, as the corner d of the arm has passed the armature, the latterwill be 'restored by the spring to its normal position,

whereby the short end of the arm will simply lie under the lower end ofthe armature, as shownin Figs. 2 and 3,wherein the arm is understood tobe in position to maintain the index-hand in the position it is toassume preparatory to a call. The arm 1) will under such conditions beheld positively subject to the position of the armature, and can by nopossibility drop until the armature has been attracted to an extent toclear its lower end from the path described by the short or inner end ofthe arm when the arm is'permitted to swing about its pivoted center, itbeing seen that the force of the spring willhold the ar mature with itsupper end against a stop or abutment and its lower end away from themagnet, and that any tendency on the part of the arm to drop will, solong as the armature remains unattracted by the magnet, simply assist inholding the upper end of the armature against the stop or abutment; butsince the arm D binds against the armature merely to an extent that isproportional to the weight of the longer end portion of the arm thefrictional contact between the armand the armature will be slight andinsufiicient to retard the free movement of the armature when the latteris attracted by the magnet.

As a matter of principle, the armature and thearm may each be consideredas consisting of a straight piece, the slight curvatures herein shownbeing merely for appearance and to permit the mechanism to be made morecompact.

From the foregoing it will be seen that, no matter how much theapparatus may be jolted or shaken, the spring will hold the armature insteady position free from the magnet as long as the magnet remainsunexcited, and that so long as the armature is thus held the ar1n,afterit has once been swung up to the highest limit ofitsupmovement,willbepositivelyprevented from dropping.

The normal position of the armature-that is to say, its position whereinit is held by .the spring against the cam-stop E, or, in fact, anysuitable stop located at such point-serves to permit the armature topresent a positive check or stop to the downswing of the arm D when sucharm has been brought into position to place the index in its normal orset condition and bring the short or tail end of the arm D under thelower end of the armature. The tendency of the weighted or heavier endof the arm D" to swing down can in nowise affect the armature, the shortend of arm D being simply pressed up against the lower end of thearmature in a line of force toward'the pivot and in a direction to pressthe upper end of the armature against the stop E, thereby simplyco-operating with the spring in holding the lower end of the armatureaway from the electro-magnet, and yet a slight excitation of theelectro-magnet will attract the armature and readily liberate thearm Dwhereby the great desideratum of the use of a light economical batterycan be attained. This is due to the fact that while the spring actsagainst the armature above the pivot of the latter the armature,whenattracted,will be atthe annunciator is employed is jolted, the arm, whenonce under the end of the armature, cannot escape until the lower end ofthe armature has been attracted by the electro-magnet.

The index-spindle D extends through the back plate, and in rear of thelatter has a bearing conveniently formed in a cleat, I, that is securedto the back plate.

The stud G, to which the lower end of the spring is secured, isdesirably located directly over the pivotal center of the arm D, so thatwhen the arm is swung suddenly up to an extent to permit the corner (Zof its short end to pass the lower end of the armature the stud G mayserve as a stop for limiting the upward swing of the arm,which latter,after striking such stop,will fall back into the position shown in Figs.2 and 3.

The stop E subserves the purpose of an abutment, against which the upperend ofthe armature will be held by the spring so long as the armature isunattracted by the magnet, and as a stop or abutment it necessarilylimits the extent to which the lower end of the armature can be swungaway from the magnet. It is desired, however, to further utilize thisstop, and to such end it is made can'1-shaped,whereby not only can theextent to which the armature may be thrown away from the magnet bedetermined, but also the extent of contact between the lower end of thearmature and the arm D be regulated, thereby varying the extent to whichthe armature must move before releasing the arm, and further permittingthe desired position of the index preparatory to a call to be accuratelydetermined, it being obvious that by adjusting the canrstop E the normalposition of the armature can be somewhat varied, and that the positionof the arm D will depend upon such normal position of the armature.

The stop F serves to prevent the armature from being drawn into actualcontact with the magnet, and is desirably made can'rshaped, so that thespace which it is desired shall intervene between the magnet and thearmature when the latter is attracted can be regulated with greatnicety.

The stop H determines the drop of the arm D and hence determines theextent of movement on the part of the index after the arm has beenreleased of the armature. This stop is also made cam-shaped, whereby thethrow of the arm can be accurately determined, and hence where quite anumber of index-hands are employed the stops of the nature of stop H canbe set so that the several indexhands shall have a uniform extent ofthrow, and thereby be made to assume corresponding positions. In thisconnection it may be observed that an annunciator wherein theindex-hands, either originally or as a result of use, point in differentdirections at times when they should point in one direction is aconstant source of annoyance.

The slide K, (shown in Figs. 2 and 5,) for lifting the arm D", consistsof a couple of sliderods, is, rigidly connected together at their lowerends by a cross-piece, k, with one of the rods provided with a pin, kfor engaglng the arm D when the slide is raised.

The posts L on the back plate are provided with guide-openings for theslide-rods, and serve to guide and steady the same. It is understood,however, that the slide will be provided with a suitable handle, it, asin Fig. 1, and that the rods 75 can be lengthened and multiplied, thenumber of pins it increased, and additional guide-posts L employed, allproportionally to the size of the apparatus,wh1ch, of course, willdepend upon the number of 111- dex devices employed.

In Fig. 1 provision is made for operating four separate index hands ordevices.

That I claim as my invention is- 1. In an electric annuneiator, thecombination, substantially as herein described, of the electro-magnet,the oscillatory armature A, consisting of a proximately-straight barplvoted between its ends, the spring applied to act against the upperend of the armature above the pivot thereof, and the arm D ot the indexdevice,arranged to engage and bear upwardly against the lower extremityof the said armature and below the pivot thereof when said arm is inposition to place the index in its set or normal condition,substantially as described.

2. In an electric annunciator, the combination, substantially as hereindescribed, of the electro-magnet, the oscillatory armature A, pivotedbetween its ends, the vibratory arm D ot'the index device,arranged toengage against the lower extremity of the armature when said arm is inposition to place the index in its normal or set condition, the springapplied against the upper end of the armature, and the cam E,againstwhich the upper end of the armature is normally maintained by thespring, substantially as set forth.

3. The combination, substantially as de scribed, of the electro-magnet,the oscillatory spring -controlled armature A, pivoted between its ends,the cam-stopsE and F, between which the upper end of the oscillatoryarmature is extended, and the arm D of the index device, arranged toengage against the lower extremity of the armature when said arm is inposition to place the index in its normal or set condition,substantially as described.

4. In an electric annnnciator, the combination, with the vibratory arm Dof the index device, ofthe canrstop H, for limiting the extent of dropon the part of said arm, substantially as described- JOHN \VILLIAMHOFFMAN.

Witnesses:

E. L. GAGE, F. M. UNGER.

